[PATCH v2 1/4] kbuild: use $(CC_VERSION_TEXT) to evaluate CC_IS_GCC and CC_IS_CLANG

[Masahiro Yamada]

The result of '$(CC) --version | head -n 1' is already computed by the
top Makefile, and stored in the environment variable, CC_VERSION_TEXT.

'echo' is probably less expensive than the two commands $(CC) and
'head' although this optimization is not noticeable level.

Signed-off-by: Masahiro Yamada <masa...@kernel.org>
---

Changes in v2:
- new patch

init/Kconfig | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index 9e22ee8fbd75..5f797df3f043 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -9,7 +9,7 @@ config DEFCONFIG_LIST
default "arch/$(SRCARCH)/configs/$(KBUILD_DEFCONFIG)"

config CC_IS_GCC
- def_bool $(success,$(CC) --version | head -n 1 | grep -q gcc)
+ def_bool $(success,echo "$(CC_VERSION_TEXT)" | grep -q gcc)

config GCC_VERSION
int
@@ -21,7 +21,7 @@ config LD_VERSION
default $(shell,$(LD) --version | $(srctree)/scripts/ld-version.sh)

config CC_IS_CLANG
- def_bool $(success,$(CC) --version | head -n 1 | grep -q clang)
+ def_bool $(success,echo "$(CC_VERSION_TEXT)" | grep -q clang)

config CLANG_VERSION
int
--
2.25.1

[Nathan Chancellor]

On Thu, Apr 23, 2020 at 11:23:51PM +0900, Masahiro Yamada wrote:
> The result of '$(CC) --version | head -n 1' is already computed by the
> top Makefile, and stored in the environment variable, CC_VERSION_TEXT.
>
> 'echo' is probably less expensive than the two commands $(CC) and
> 'head' although this optimization is not noticeable level.
>
> Signed-off-by: Masahiro Yamada <masa...@kernel.org>

Reviewed-by: Nathan Chancellor <natecha...@gmail.com>
Tested-by: Nathan Chancellor <natecha...@gmail.com>

[Masahiro Yamada]

On Thu, Apr 23, 2020 at 11:24 PM Masahiro Yamada <masa...@kernel.org> wrote:
>
> The result of '$(CC) --version | head -n 1' is already computed by the
> top Makefile, and stored in the environment variable, CC_VERSION_TEXT.
>
> 'echo' is probably less expensive than the two commands $(CC) and
> 'head' although this optimization is not noticeable level.
>
> Signed-off-by: Masahiro Yamada <masa...@kernel.org>

Applied to linux-kbuild.

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--
Best Regards
Masahiro Yamada